Plasma etching method, pattern forming method and cleaning method

Abstract

A plasma etching method is performed by forming a desired pattern of a mask into a film including a zirconium oxide film by plasma etching with plasma generated from a first gas. The first gas consists of at least one chloride-containing gas of the group of boron trichloride, tetrachloromethane, chloride and silicon tetrachloride, at least one hydrogen-containing gas of the group of hydrogen bromide, hydrogen and methane, and a noble gas. An underlying film of a silicon oxide film or an amorphous carbon film is provided underneath the zirconium oxide film, and an etching selectivity of the zirconium oxide film to the underlying film is greater than or equal to one.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This patent application is based upon and claims the benefit of priority of Japanese Patent Application No. 2015-81019, filed on Apr. 10, 2015, the entire contents of which are incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to a plasma etching method, a pattern forming method and a cleaning method.[0004]2. Description of the Related Art[0005]A technique is known of finely processing a target film to be etched by a plasma etching by generating plasma from a gas. For example, Japanese Laid-Open Patent Application Publication No. 2005-252186 discloses a technique of depositing a silicon oxide film on a substrate by a thermal oxidation process first, then depositing a high-k (high-dielectric-constant) film on the silicon oxide film by CVD (Chemical Vapor Deposition), and etching the high-k film by using plasma generated from a gas such as Cl2. Also, Japanese Laid-...

AI Technical Summary

Benefits of technology

The present invention provides a method to selectively etch a film, such as a zirconium oxide film, using plasma generated from a first gas. The gas includes at least one chloride-containing gas and at least one hydrogen-containing gas. The etching selectivity of the zirconium oxide film to an underlying film (e.g. silicon oxide or amorphous carbon film) is greater than or equal to 1. This allows for efficient and selective etching of zirconium oxide films without compromising the integrity of the underlying film.

Problems solved by technology

However, when etching selectivity of the target film to be etched, such as the high-k film, to an underlying film cannot be sufficiently obtained, forming the deep and vertical holes and trenches into the target film to be etched becomes difficult, and the etching properties become worse.

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